blob: 2faa9a9d84b1fd2246b160133cc9b15e494d076f (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
|
#pragma once
#include <mbgl/gl/gl.hpp>
#include <mbgl/gl/context.hpp>
#include <mbgl/platform/log.hpp>
#include <mbgl/util/noncopyable.hpp>
#include <mbgl/util/optional.hpp>
#include <memory>
#include <cstdlib>
#include <cassert>
#include <stdexcept>
namespace mbgl {
template <
GLsizei item_size,
GLenum target = GL_ARRAY_BUFFER,
GLsizei defaultLength = 8192,
bool retainAfterUpload = false
>
class Buffer : private util::noncopyable {
static_assert(target == GL_ARRAY_BUFFER || target == GL_ELEMENT_ARRAY_BUFFER,
"target must be one of GL_ARRAY_BUFFER or GL_ELEMENT_ARRAY_BUFFER");
public:
~Buffer() {
cleanup();
}
// Returns the number of elements in this buffer. This is not the number of
// bytes, but rather the number of coordinates with associated information.
GLsizei index() const {
return static_cast<GLsizei>(pos / itemSize);
}
bool empty() const {
return pos == 0;
}
// Transfers this buffer to the GPU and binds the buffer to the GL context.
void bind(gl::Context& context) {
const bool initialized { buffer };
if (!initialized) {
buffer = context.createBuffer();
}
if (target == GL_ARRAY_BUFFER) {
context.vertexBuffer = *buffer;
} else {
context.elementBuffer = *buffer;
}
if (!initialized) {
if (array == nullptr) {
Log::Debug(Event::OpenGL, "Buffer doesn't contain elements");
pos = 0;
}
MBGL_CHECK_ERROR(glBufferData(target, pos, array, GL_STATIC_DRAW));
if (!retainAfterUpload) {
cleanup();
}
}
}
void cleanup() {
if (array) {
free(array);
array = nullptr;
}
}
gl::BufferID getID() const {
return buffer ? *buffer : 0;
}
// Uploads the buffer to the GPU to be available when we need it.
void upload(gl::Context& context) {
if (!buffer) {
bind(context);
}
}
protected:
// increase the buffer size by at least /required/ bytes.
void *addElement() {
if (buffer) {
throw std::runtime_error("Can't add elements after buffer was bound to GPU");
}
if (length < pos + itemSize) {
while (length < pos + itemSize) length += defaultLength;
array = realloc(array, length);
if (array == nullptr) {
throw std::runtime_error("Buffer reallocation failed");
}
}
pos += itemSize;
return reinterpret_cast<char *>(array) + (pos - itemSize);
}
public:
static const size_t itemSize = item_size;
private:
// CPU buffer
GLvoid *array = nullptr;
// Byte position where we are writing.
GLsizeiptr pos = 0;
// Number of bytes that are valid in this buffer.
size_t length = 0;
// GL buffer object handle.
mbgl::optional<gl::UniqueBuffer> buffer;
};
} // namespace mbgl
|
